I agree 100 percent. A lot of people will be discouraged to see their post value go down with the coin and most of them wont understand it. I like your idea of using sp and steem only because it gives the publisher a straight forward  answer as to what their post is worth. Furthermore, The whole SBD, Steem And Steem Power setup is very confusing to newbies and has no clear answer as to what is what.. People are left to figure this out on their own.